<?php
abstract class CV_Singleton implements CV_Singleton_Interface{
	protected static $instance = array();
	public static function _instance( $class ){
		if( !isset(self::$instance[$class]) ){
			self::$instance[$class] = new $class();
		}
		return self::$instance[$class];
	}
	protected function __construct(){}
}
interface CV_Singleton_Interface{
	public static function instance();
}